• Journal of the Earthquake Engineering Society of Korea
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• v.18 no.6
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• pp.301-308
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• 2014

A suspension bridge is a type of bridge in which the beam is suspended by load-bearing cables. There are two classifications: the self-anchored suspension bridge has the main cable anchored to the bridge girders, and the earth-anchored suspension bridge has the main cable anchored to a large anchorage. Although a suspension bridge is structurally safe, it is prone to be damaged by various actions such as hurricanes, tsunamis and terrorist incidents because its cables are exposed. If damage to a cable eventually leads to the cable rupture, the bridge may collapse. To avoid these accidents, studies on the dynamic behavior of cable bridges due to the cable rupture have been carried out. Design codes specify that the calculated DAF (dynamic amplification factor) should not exceed a certain value. However, it has been difficult to determine DAFs effectively from dynamic analysis, and thus no systematic approach has been suggested. The current study provides a guideline to determine DAFs reliably from the dynamic analysis results and summarizes the results by applying the method to an earth-anchored suspension bridge. In the study, DAFs were calculated at the location of four structural parts, girders, pylons, main cable and hangers, with variations in the rupture time.

• Journal of Korean Society for Atmospheric Environment
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• v.6 no.2
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• pp.155-160
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• 1990

During the period from Mar. 1985 to Feb. 1988, airborne particulate matters were collected and size fractionated by the ANdersen high volume air sampler in Seoul. The concentrations of several heavy metals (Pb, Cu, Zn, Fe, Mn) and benzo(a)pyrene were determined to investigate the size distributions and seasonal variations. And with respect to seven components in the total suspended particulate (TSP), the factor analysis was performed for three groups such as the coarse particles (> 2 $\mu$m), fine particles (< $\mu$m) and TSP. As a result of factor analysis by using the varimax method, the chemical components in the TSP were able to characterize with two principal factors. The first factor, F1 was considered to be a factor indicating the contribution of natural sources and the second factor, F2 was a factor indicating the degree of artificial sources. Each components in the TSP was divided into two main groups of components originated from soil and/or road dust and pollutants originated from automobiles and/or human work.

• Elastomers and Composites
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• v.32 no.1
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• pp.20-28
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• 1997

This study have Investigated the effect of various factors related to the physical properties of vulcanizated rubber compounds. rubber type, carbon black type and carbon black loading were selected as main factors and evaluation were tested by tables of orthogonal arrays with 3 factors and 3 levels. rubber types have affected cure time, tensile strength, and $T_g$ as main factor and carbon black loading have affected viscosity, scorch time, maximum torque, hardness, 300% modulus, rebound, heat build-up, $0\;&\;60^{\circ}C$ tangent delta, PICO and CUT/CHIP loss as main factor but the effects of carbon black type have affected only bound rubber content.

• Journal of the Korea Concrete Institute
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• v.18 no.5 s.95
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• pp.639-648
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• 2006

A shear experiment of one-way monotonic loading was carried out with the shear span ratio as the main experimental variable for reinforced concrete beam. Using the finite element analysis as the experimental analysis tool and the analysis method to compute the shear resistance of small shear span ratio, a new macro-model composed of crooked main strut and sub strut is proposed in consideration of the effect of bond action between re-bar and concrete based on the experimental result. The experimental finding affirmed the validity of the proposed macro-model when the shear span ratio was at or below 0.75 and confirmed that the experimental result was the most consistent with the computed analysis result when the effective factor of concrete compressive strength was set at 0.75.

• Journal of Environmental Science International
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• v.8 no.3
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• pp.331-336
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• 1999

The monthly water quality data measured at 14 stations located in the Geum-River watershed were clustered into 2 to 7 clusters. Furthermore, factor analyses were conducted on Gabcheon and Yugucheon to characterize the water qualtiy, based on the information obtained from the results of culster analysis. The results of cluster analysis show that the water quality charactersitic of main stream of the Geum-River is somewhat different from that of substream of the Geum-River. Furthermore, the water quality characteristic of Gabcheon which is expected to have the most serious water quality problems in the Geum-River watershed shows the most different water quality characteristic from Yugucheon. Based ont he factor loadings in each factor, Gabcheon and Yugucheon have their own water quality characteristics. This is mainly because of composite factors such as different population density, industrial activities, and land use conditions in Gabcheon and Yugucheon subwatersheds.

• Earthquakes and Structures
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• v.16 no.6
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• pp.655-664
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• 2019

Behavior factor of a structure plays a crucial role in designing and predicting the inelastic responses of it. Recently, irregular buildings have been interested in many designers. To design irregular structures, recognizing the inelastic behavior of them is necessary. The main objective of this study is to determine the behavior factor of irregular Reinforced Concrete Moment Resisting Frames (RCMRFs) via nonlinear Incremental Dynamic Analysis (IDA). To do so, first, several frames are designed according to the regulations of the Iranian national building code. Then the nonlinear incremental dynamic analysis is performed on these structures and the behavior factors are achieved. The acquired results are compared with those obtained using pushover analysis and it is shown that the behavior factors acquired from the nonlinear incremental dynamic analysis are somewhat larger than those obtained from pushover analysis. Eventually, two practical relations are proposed to predict the behavior factor of irregular RCMRFs. Since these relations are based on the simple characteristics of frames such as: irregularity indices, the height and fundamental period, the behavior factor of irregular RCMRFs can be achieved efficiently using these relations. The proposed relations are applied to design of four new irregular RCMRFs and the outcomes confirm the accuracy of the aforementioned relations.

• Korean journal of food and cookery science
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• v.27 no.6
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• pp.825-838
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• 2011

The main purposes of this study were to assess coffee shop use and to identify the influence of physical environment of a coffee chop on customer behavioral intention. The survey was administered from April to May 2011, targeting twenties college students in Seoul, Gyeonggi Province. A total of 174 copies of the questionnaire were collected for the data analyses such as frequency test, descriptive analysis, chi-square analysis, reliability test, factor analysis, ANOVA, Duncan's multiple range test and multiple regression analysis using SPSS 17.0 program. The main results of this study were as follows: The number of visits was once or twice a week. Students went with their friends to the coffee shop. Most of the students answered that they visit the coffee shop at any time. The main purpose of visit was to have time to relax. The main source in choosing a coffee shop was recommendation from others. The main criterion for the selection of the coffee shop was atmosphere. Americano was a favorite drink. Coffee was drunk with a cake. Expenditure per visit was 3,000~5,000 won. The choice of the coffee shop was selected by the student. The factor analysis identified seven underlying dimensions of coffee shop physical environment perceptions (seating comfort, attractiveness, cleanliness, harmony, ambient condition, congestion, amenity) and one dimension of customer behavioral intention. Through multiple regression analyses, four determinants (attractiveness, cleanliness, amenity, ambient condition) were found to have the greatest impact on customer behavioral intention.

• Journal of the Korea Safety Management & Science
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• v.23 no.2
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• pp.9-17
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• 2021

As interest in vocational competency development projects increases, support is increasing. In this study, in order to study ways to improve participation in vocational competency development training, related factors are selected and the main factors influencing them are derived. The main factors were influencing factors were identified and ways to improve participation rate of vocational competency development were studied. Variables were selected through prior research, and data were collected and analyzed through in-depth group interviews. Based on factor analysis and reliability analysis, as a result of confirming the factors that influence the plan for improving participation in vocational competency development training by applying the backward stage selection (condition) method of logistic regression analysis, the case of respect for minorities in the 7-point Likert scale The closer to 7 was, the higher the probability of being classified as having never participated, and the other factors except minority respect, Likert scale closer to 7 indicates higher probability of bening classified as having never participated, except for the minority respect factor. Therefore, it was confirmed that lowering the scale of the factor of respect for minority, which is job satisfaction, and increasing the factors of individual characteristics such as annual salary and organizational commitment, training system for job satisfaction, and quality assurance have effects on improving participation rates in vocational competency development training.

• Journal of the Korean Institute of Landscape Architecture
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• v.24 no.2
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• pp.43-51
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• 1996

The main purpose of this study is to obtain information on users' socio-economic characteristics, pattern of main use activities, and visit motivation in recreation forests. From June to September in 1994, respondents were selected 548 adults more than 18 years old from 6 recreation forests which were classified 3 recreation forest types as 2 recreation forest in national forest, 2 in public forest, and 2 in private forest. Analysis of data was conducted through frequency and factor analysis. The most of noticeable characteristics of users were rather 30's age group, high education level, company workers, city residents. The major preference activities in recreation forest were resting, enjoying green shower, and walking. In 24 items of visit motivation, resting, releasing stress, enjoying in a cool forest & valley, and contacting close to nature were high preference, while buying special product, and contacting close to nature were high preference, while buying special product, having enough and to money, observing wildlife, and training body & mind were low preference. The remarkable difference in 3 recreation forest types didn't present. Eight dimensions of motivation were classified through factor analysis.

• Journal of Power Electronics
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• v.12 no.1
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• pp.164-171
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• 2012

Variable step size maximum power point trackers (MPPTs) are widely used in photovoltaic (PV) systems to extract the peak array power which depends on solar irradiation and array temperature. One essential factor which judges system dynamics and steady state performances is the scaling factor (N), which is used to update the controlling equation in the tracking algorithm to determine a new duty cycle. This paper proposes a novel stability study of variable step size incremental resistance maximum power point tracking (INR MPPT). The main contribution of this analysis appears when developing the overall small signal model of the PV system. Therefore, by using linear control theory, the boundary value of the scaling factor can be determined. The theoretical analysis and the design principle of the proposed stability analysis have been validated using MATLAB simulations, and experimentally using a fixed point digital signal processor (TMS320F2808).